This invention relates to novel aromatic diamines and more particularly to aromatic polyamideimides synthesized therefrom by condensation polymerization with trimellitic acid anhydride or trimellitic anhydride acid chloride or trimellitic acid.
The need for high polymeric coating materials which exhibit good high temperature stability has been partially satisfied by the synthesis or aromatic polyimides by the condensation polymerization of arylene diamines with aromatic dianhydrides. For example, polyimides prepared in one instance from phenylenediamine and pyromellitic dianhydride having repeating units are presented by the formula ##SPC1##
Have been recommended for use as wire coatings. While such compounds fulfill the demands for high temperature stability, they are deficient in other properties such as adhesion, elongation, ease of drying, solubility in organic solvents, and tractability or flow at application temperature. Some of these difficulties were overcome by either changing the imide linkages to amide linkages or to amide-imide linkages or by replacing the arylene moiety of the diamine with polynuclear entities such as: ##SPC2##
Where R is alkylidene --O--, --S--, ##STR1## and the like.
As so often happens in custom making high polymers to improve a particular property, the desired end is achieved only by the loss of one or more of the other properties. Thus for example, the substitution of amide linkages for imide linkages in polymers made from simple aromatic diamines improves tractability but renders the polymer less thermally and oxidiatively stable, (J.I. Jones et al., Chemistry and Industry, 1686, Sept. 22, 1962). The polymers of this invention overcome the difficulties associated with polyimides and at the same time are useful in a wider range of applications than can be considered for any previously available high temperature polymer.